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<pre><span class="comment"> /****************************************************************************
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 ** Copyright (C) 2005-2008 Trolltech ASA. All rights reserved.
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<span class="comment"> /*
     treemodel.cpp

     Provides a simple tree model to show how to create and use hierarchical
     models.
 */</span>

 #include &lt;QtGui&gt;

 #include &quot;treeitem.h&quot;
 #include &quot;treemodel.h&quot;

 TreeModel::TreeModel(const QString &amp;data, QObject *parent)
     : QAbstractItemModel(parent)
 {
     QList&lt;QVariant&gt; rootData;
     rootData &lt;&lt; &quot;Title&quot; &lt;&lt; &quot;Summary&quot;;
     rootItem = new TreeItem(rootData);
     setupModelData(data.split(QString(&quot;\n&quot;)), rootItem);
 }

 TreeModel::~TreeModel()
 {
     delete rootItem;
 }

 int TreeModel::columnCount(const QModelIndex &amp;parent) const
 {
     if (parent.isValid())
         return static_cast&lt;TreeItem*&gt;(parent.internalPointer())-&gt;columnCount();
     else
         return rootItem-&gt;columnCount();
 }

 QVariant TreeModel::data(const QModelIndex &amp;index, int role) const
 {
     if (!index.isValid())
         return QVariant();

     if (role != Qt::DisplayRole)
         return QVariant();

     TreeItem *item = static_cast&lt;TreeItem*&gt;(index.internalPointer());

     return item-&gt;data(index.column());
 }

 Qt::ItemFlags TreeModel::flags(const QModelIndex &amp;index) const
 {
     if (!index.isValid())
         return 0;

     return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
 }

 QVariant TreeModel::headerData(int section, Qt::Orientation orientation,
                                int role) const
 {
     if (orientation == Qt::Horizontal &amp;&amp; role == Qt::DisplayRole)
         return rootItem-&gt;data(section);

     return QVariant();
 }

 QModelIndex TreeModel::index(int row, int column, const QModelIndex &amp;parent)
             const
 {
     if (!hasIndex(row, column, parent))
         return QModelIndex();

     TreeItem *parentItem;

     if (!parent.isValid())
         parentItem = rootItem;
     else
         parentItem = static_cast&lt;TreeItem*&gt;(parent.internalPointer());

     TreeItem *childItem = parentItem-&gt;child(row);
     if (childItem)
         return createIndex(row, column, childItem);
     else
         return QModelIndex();
 }

 QModelIndex TreeModel::parent(const QModelIndex &amp;index) const
 {
     if (!index.isValid())
         return QModelIndex();

     TreeItem *childItem = static_cast&lt;TreeItem*&gt;(index.internalPointer());
     TreeItem *parentItem = childItem-&gt;parent();

     if (parentItem == rootItem)
         return QModelIndex();

     return createIndex(parentItem-&gt;row(), 0, parentItem);
 }

 int TreeModel::rowCount(const QModelIndex &amp;parent) const
 {
     TreeItem *parentItem;
     if (parent.column() &gt; 0)
         return 0;

     if (!parent.isValid())
         parentItem = rootItem;
     else
         parentItem = static_cast&lt;TreeItem*&gt;(parent.internalPointer());

     return parentItem-&gt;childCount();
 }

 void TreeModel::setupModelData(const QStringList &amp;lines, TreeItem *parent)
 {
     QList&lt;TreeItem*&gt; parents;
     QList&lt;int&gt; indentations;
     parents &lt;&lt; parent;
     indentations &lt;&lt; 0;

     int number = 0;

     while (number &lt; lines.count()) {
         int position = 0;
         while (position &lt; lines[number].length()) {
             if (lines[number].mid(position, 1) != &quot; &quot;)
                 break;
             position++;
         }

         QString lineData = lines[number].mid(position).trimmed();

         if (!lineData.isEmpty()) {
             <span class="comment">//</span> Read the column data from the rest of the line.
             QStringList columnStrings = lineData.split(&quot;\t&quot;, QString::SkipEmptyParts);
             QList&lt;QVariant&gt; columnData;
             for (int column = 0; column &lt; columnStrings.count(); ++column)
                 columnData &lt;&lt; columnStrings[column];

             if (position &gt; indentations.last()) {
                 <span class="comment">//</span> The last child of the current parent is now the new parent
                 <span class="comment">//</span> unless the current parent has no children.

                 if (parents.last()-&gt;childCount() &gt; 0) {
                     parents &lt;&lt; parents.last()-&gt;child(parents.last()-&gt;childCount()-1);
                     indentations &lt;&lt; position;
                 }
             } else {
                 while (position &lt; indentations.last() &amp;&amp; parents.count() &gt; 0) {
                     parents.pop_back();
                     indentations.pop_back();
                 }
             }

             <span class="comment">//</span> Append a new item to the current parent's list of children.
             parents.last()-&gt;appendChild(new TreeItem(columnData, parents.last()));
         }

         number++;
     }
 }</pre>
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